Russia says Ukraine has launched "a terrorist drone attack" on Moscow, with several buildings damaged.
Speaking on Russian state television, Putin claimed the attack on Moscow was a "response" to an air strike against Ukraine's military intelligence agency.
It is the first time Moscow has been so heavily targeted in a single operation, but Ukraine denies carrying out the strikes.
The US has said it does not support the drone attacks in Russia, as Russia's Wagner group hits out at the Kremlin's defence ministry for not doing enough to prevent such attacks.